2,806 research outputs found
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Fast and deep deformation approximations
Character rigs are procedural systems that compute the shape of an animated character for a given pose. They can be highly complex and must account for bulges, wrinkles, and other aspects of a character's appearance. When comparing film-quality character rigs with those designed for real-time applications, there is typically a substantial and readily apparent difference in the quality of the mesh deformations. Real-time rigs are limited by a computational budget and often trade realism for performance. Rigs for film do not have this same limitation, and character riggers can make the rig as complicated as necessary to achieve realistic deformations. However, increasing the rig complexity slows rig evaluation, and the animators working with it can become less efficient and may experience frustration. In this paper, we present a method to reduce the time required to compute mesh deformations for film-quality rigs, allowing better interactivity during animation authoring and use in real-time games and applications. Our approach learns the deformations from an existing rig by splitting the mesh deformation into linear and nonlinear portions. The linear deformations are computed directly from the transformations of the rig's underlying skeleton. We use deep learning methods to approximate the remaining nonlinear portion. In the examples we show from production rigs used to animate lead characters, our approach reduces the computational time spent on evaluating deformations by a factor of 5×-10×. This significant savings allows us to run the complex, film-quality rigs in real-time even when using a CPU-only implementation on a mobile device
Searching for additional heating - [OII] emission in the diffuse ionized gas of NGC891, NGC4631 and NGC3079
We present spectroscopic data of ionized gas in the disk--halo regions of
three edge-on galaxies, NGC 891, NGC 4631 and NGC 3079, covering a wavelength
range from [\ion{O}{2}] 3727\AA to [\ion{S}{2}] 6716.4\AA.
The inclusion of the [\ion{O}{2}] emission provides new constraints on the
properties of the diffuse ionized gas (DIG), in particular, the origin of the
observed spatial variations in the line intensity ratios. We used three
different methods to derive electron temperatures, abundances and ionization
fractions along the slit. The increase in the [\ion{O}{2}]/H line ratio
towards the halo in all three galaxies requires an increase either in electron
temperature or in oxygen abundance. Keeping the oxygen abundance constant
yields the most reasonable results for temperature, abundances, and ionization
fractions. Since a constant oxygen abundance seems to require an increase in
temperature towards the halo, we conclude that gradients in the electron
temperature play a significant role in the observed variations in the optical
line ratios from extraplanar DIG in these three spiral galaxies.Comment: 43 pages, 29 figure
CORSS: Cylinder Optimization of Rings, Skin, and Stringers
Launch vehicle designs typically make extensive use of cylindrical skin stringer construction. Structural analysis methods are well developed for preliminary design of this type of construction. This report describes an automated, iterative method to obtain a minimum weight preliminary design. Structural optimization has been researched extensively, and various programs have been written for this purpose. Their complexity and ease of use depends on their generality, the failure modes considered, the methodology used, and the rigor of the analysis performed. This computer program employs closed-form solutions from a variety of well-known structural analysis references and joins them with a commercially available numerical optimizer called the 'Design Optimization Tool' (DOT). Any ring and stringer stiffened shell structure of isotropic materials that has beam type loading can be analyzed. Plasticity effects are not included. It performs a more limited analysis than programs such as PANDA, but it provides an easy and useful preliminary design tool for a large class of structures. This report briefly describes the optimization theory, outlines the development and use of the program, and describes the analysis techniques that are used. Examples of program input and output, as well as the listing of the analysis routines, are included
Warmte-koude opslag en duurzaam gebruik van de ondergrond
Warmte koude opslag (WKO) is een energie en kostenbesparende methode voor het verwarmen en koelen van gebouwen. Open WKO systemen pompen het grondwater heen en weer om het gebouw te koelen of te verwarmen. Gesloten WKO systemen gebruiken alleen de warmte van het grondwater om huizen te verwarmen of te koelen. In Nederland is er de laatste jaren een sterke en door de overheid gestimuleerde groei van het aantal WKO systemen. Gesloten WKO systemen zouden een risico kunnen vormen voor de kwaliteit van het grondwater door het groot aantal perforaties van de ondergrond en door het mogelijke lekken van koelvloeistof. Bij open WKO systemen moet voorkomen worden dat verschillende grondwaterlagen gemengd worden waardoor ongewenste geochemische en microbiologische processen optreden. In principe kan een open WKO systeem wel op een vervuilde locatie worden toegepast, maar er is specifiek maatwerk nodig om de verspreiding van de vervuiling te beperken. De bescheiden temperatuursveranderingen die door WKO systemen worden opgewekt in het grondwater vormen slechts een gering risico voor geochemische processen. Deze temperatuursveranderingen zouden in principe wel aanleiding kunnen geven tot een toename van het aantal ziektekiemen in het grondwater. Daarom is het belangrijk dat er voldoende afstand is tussen een drinkwaterwinning en de omringende WKO installaties. Verder onderzoek is nodig om vast te stellen welke invloed WKO installaties hebben op de bacteriën in het grondwater. Het opslaan van heet (90 °C) grondwater heeft een groot aantal milieubezwaren. De Europese kaderrichtlijn water ziet ook de inbreng van warmte in het grondwater als een mogelijke verontreiniging wanneer daar nadelige gevolgen voor mensen of ecosystemen aan verbonden zijn. Het toezicht van de provincies op het groeiende aantal WKO systemen in de praktijk verdient nadere aandacht
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Chronic nicotine administration restores brain region specific upregulation of oxytocin receptor binding levels in a G72 mouse model of schizophrenia.
Nicotine dependence and schizophrenia are two mental health disorders with remarkably high comorbidity. Cigarette smoking is particularly prevalent among schizophrenic patients and it is hypothesized to comprise a form of self-medication for relieving cognitive deficits in these patients. Emerging evidence suggests a role of the neurohypophysial peptide oxytocin in the modulation of drug addiction, as well as schizophrenia symptomology; however, the underlying mechanism remains unclear. Therefore, we sought to investigate the effects of chronic nicotine administration on oxytocin receptor (OTR) binding in the brain of a transgenic mouse model of schizophrenia that carries a bacterial artificial chromosome of the human G72/G30 locus (G72Tg). Female wild-type (WT) and heterozygous G72 transgenic CD-1 mice were treated with a chronic nicotine regimen (24 mg/kg/day, osmotic minipumps for 14 days) and quantitative autoradiographic mapping of oxytocin receptors was carried out in brains of these animals. OTR binding levels were higher in the cingulate cortex (CgCx), nucleus accumbens (Acb) and central amygdala (CeA) of saline treated G72Tg mice compared with WT control mice. Chronic nicotine administration reversed this upregulation in the CgCx and CeA. Interestingly, chronic nicotine administration induced an increase in OTR binding in the CeA of solely WT mice. These results indicate that nicotine administration normalizes the dysregulated central oxytocinergic system of this mouse model of schizophrenia and may contribute towards nicotine's ability to modulate cognitive deficits which are common symptoms of schizophrenia. This article is protected by copyright. All rights reserved
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